UefiPayloadPkg: Add library for logging to EC

Make use of the SMFI command interface to forward logs from edk2 to
System76 EC.

MdeModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.c

@@ -17,6 +17,7 @@
 #include <Library/PciLib.h>
 #include <Library/PlatformHookLib.h>
 #include <Library/BaseLib.h>
+#include <Library/System76EcLib.h>
 
 //
 // PCI Defintions.
@@ -601,6 +602,8 @@ SerialPortWrite (
   UINTN  Result;
   UINTN  Index;
   UINTN  FifoSize;
+  UINT8  *BufPtr = Buffer;
+  UINTN  Bytes = NumberOfBytes;
 
   if (Buffer == NULL) {
     return 0;
@@ -663,6 +666,9 @@ SerialPortWrite (
       SerialPortWriteRegister (SerialRegisterBase, R_UART_TXBUF, *Buffer);
     }
   }
+
+  System76EcWrite(BufPtr, Bytes);
+
   return Result;
 }
 

MdeModulePkg/Library/BaseSerialPortLib16550/BaseSerialPortLib16550.inf

@@ -18,12 +18,14 @@
 [Packages]
   MdePkg/MdePkg.dec
   MdeModulePkg/MdeModulePkg.dec
+  UefiPayloadPkg/UefiPayloadPkg.dec
 
 [LibraryClasses]
   PcdLib
   IoLib
   PlatformHookLib
   PciLib
+  System76EcLib
 
 [Sources]
   BaseSerialPortLib16550.c